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Forum Index : Electronics : F&P pole reduction - help
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| Rubes Newbie  Joined: 01/05/2009 Location: Posts: 36 |
In an attempt to salvage something from a f&p vawt see Thread here I am trying to reduce the drag so as to maintain rpms (Currently self starts and runs at +-120 - 150rpms in stiff breeze with stator removed). With a full f&p stator (no load, 2 pole star) it does not maintain rpms (could this be current eddy load?). Would it help to remove some poles (see diagram) and if so would the wiring as per diagram still be correct. Or would increasing the air gap help (Obvoisly both solutions would have a reduced output)(diagram plagarised and adapted from www.thebackshed.com) 
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Tinker Guru  Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Have you tried to convert it to 7 phase? You need the new magnet rotor running on the old stator. There is no static drag with this combination, only whatever electric load you put on it. My new magnet rotor was not very expensive, not sure if they are on junked machines yet. Klaus |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5019 |
The 7 phase conversion will certainly eliminate cogging, but the iron losses are still there and I think thats whats killing your windmill in this case. Remember you only have a small windmill, about 1/4 the size we would usually use on a F&P, so I think you need a smaller alternator. KiwiJohn did some work with a cut down F&P stator on his exercise bike. You can see the cut down stator in the top photo on this page... http://www.thebackshed.com/windmill/articles/PedalPower_John .asp If you have a spare stator or two, it might be worth a try. Cut off a few segments and see how it goes, cut down some more and test that. If you go too far, then use a fresh stator and cut down to the previous best result. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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